ElementCollection not updated when using session.update

When having an entity with an @ElementCollection inside and an Ordinal column, calling session.update(entity) does not update the ElementCollection .

This is my entity:

@Column(nullable=true)
@OrderColumn(name="Ordinal")
@JoinTable(name= "tenor1dcurve_oislist",joinColumns=@JoinColumn(name = "Tenor1DCurve_curveName"))
@Fetch(value = FetchMode.SELECT)
@ElementCollection(fetch = FetchType.EAGER)
private List<CurveInstrument> oisList;